const arr = ["a", "b", "c"];

const iter = arr.entries();
console.log("iter:", iter);
// next函数访问
console.log("iter.next():", iter.next());
console.log("iter.next():", iter.next());
console.log("iter.next():", iter.next());
console.log("iter.next():", iter.next());

// for of迭代
for (let [k, v] of arr.entries()) {
  console.log(k, v);
}
